“The Berkeley Tuolumne Family Camp is under threat,” said Jerry Snyder, public affairs officer for the Stanislaus National Forest office of the U.S. Forest Service.

The city of Berkeley is monitoring the situation carefully. A senior city employee described the camp as being “in grave danger.”

In the past 12 hours, the Rim Fire, in the Stanislaus National Forest near Groveland (Tuolumne County), has grown in scale from just over 16,000 acres to nearly 54,000 acres, making it one of biggest active blazes in the nation. It is only 2% contained at present, compared to 5% late Wednesday night.

More than 1,350 firefighters, including a contingent from Berkeley, are battling the blaze, but crews are losing ground given dry conditions, strong winds and often inaccessible terrain.